Plate type heat-exchanger



G. c. EGENWALL ET AL 2,865,613

Dec. 23, 1958 PLATE TYPE HEAT-EXCHANGER 2 Sheets-Sheet 1 Filed Feb. 14,1955 w /R m m 01 E d a r Md C n a 7 a 1T. a u G Sven-e Knuz Jen ss'enATTORNE).

Dec. 23, 1958 c E WALL ET AL 2,865,613

PLATE TYPE HEAT-EXCHANGER Filed Feb. 14, 1955 2 Sheets-Sheet 2 GuszafConrad fyenwcfi/ and INVENTORS Sve -e Knuz Jenssen A TTORNEY.

PLATE TYPE HEAT-EXCHAN GER Gustaf Conrad Egenwall, Stockholm, and SverreKnut .lenssen, Saltsjobaden, Sweden, assignors to AktiebolagetRosenblads Patenter, Stockholm, Sweden, a corporation of SwedenApplication February 14, 1955, Serial No. 487,896

Claims priority, application Sweden February 25, 1954 2 Claims. (Cl.257-245) The present invention relates to heat exchangers of satesPatent the type comprising a plurality of pressed sheet-metal heattransmission plates which together with interposed strip-sealings orpackings extending in a loop form a stack or pile.

It is previously known in connection with heat exchangers of thisgeneral type to provide impressions in one flat surface of the platewithin the areas thereof encircled by the sealing strips, whereby theopposite fiat surface of the plate will show projections or protrusionsforming spacing elements or spacers between adjacent plates. The platesare superimposed with the spacers of any one plate extending in the samedirection as the spacers of the adjacent plate or plates.

The invention has for its primary object to arrange spacers of this typein a manner so as 'to prevent the sealing strips positively from beingforced out of their proper operative position in sealing engagement withthe plates. To this purpose the spacers form, on one hand, positiveobstacles against such displacement, and on the other hand, they willalso provide space-maintaining elements between adjacent plate-portionssituated outside the areas of these plates encircled by the sealingstrip, whereby said elements prevent these portions of the plates in thestack from getting spread apart at any place due to pressure exerted bythe sealing strip, and thus prevent the sealing strip from beingreleased.

It is also an object of the invention to combine the arrangement statedin the preceding paragraph with sealing strips which are particularlyapplicable thereto and which might be of previously known types.

The invention is mainly characterized by the feature that each one ofthe heat transmission plates is provided with such spacers which aredisposed in rows and in spaced relation in the longitudinal direction ofthe sealing strip one such row extending on each side of and adjacent tosaid sealing strip, in such a manner that said spacers engage anadjacent plate between those impressions therein which correspond to thespacers similarly arranged on the said adjacent plate.

The invention will now be explained more in detail, reference being hadto the accompanying drawings illustrating, by way of example, a fewpractical embodiments thereof, and in which:

Fig. 1 is a plan-view of a heat transmission plate and the associatedendless strip-sealing in accordance with the present invention.

Fig. 2 is a plan-view of a heat transmission plate identical to that ofFig. 1 but rotated 180 relative thereto about a central axisperpendicular to its plane.

Fig. 3 is a plan-view of the plate shown in Fig. 1 superimposed on aplate as that shown in Fig. 2 in the same manner as in an actual stackof plates.

Fig. 4 illustrates, on a larger scale. a cross-section taken on the lineIVIV of the border portion A of Fig. 3.

Fig. 5 is an enlarged plan-view of the portion A of Fig. 3 but with thespacing projections arranged in a somewhat modified manner.

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Fig. 6 is an enlarged plan-view of the portion A of Fig. 3 but with thespacing projections arranged in a fur ther modified manner.

Fig. 7 illustrates the arrangement according to Fig. 5 in cross-sectiontaken on the line VIIVII in this figure.

Fig. 8 illustrates the arrangement according to Fig. 6 in cross-sectiontaken on the line VIII-VIII in this figure.

Fig. 9 illustrates a section view of a modified arrangement according toFig. 8.

Fig. 10 is an enlarged plan-view of a border portion of Fig. 3 but withthe spacing projections further modi fied.

Fig. 11 illustrates the border portion of Fig. 10 in side view as seenfrom the left in this figure.

Fig. 12 illustrates the border portion of Fig. 10 in cross-section alongthe line XIIXII in this figure.

Fig. 13 is a cross-sectional view of a particular type of strip-sealingaccording to an embodiment of the present invention.

Referring now to the drawings more specifically, in Fig. 1 thereofnumeral 1 designates a heat transmission plate having in its fourcorners openings 2, 3, 4 and 5 which form passages for theheat-exchanging fluid. A sealing strip 6 made of elastic material, suchas rubber, extends over the upper flat surface of the plate so as toenclose the passage openings 2 and 4 whilst excluding the passageopenings 3 and 5, the latter openings being encircled by separatesealing strips 7 and 8, respectively.

Fig. 2 illustrates a plate identical to that of Fig. 1 but being rotatedabout an axis perpendicular to the plane of the plate relative to theposition of the plate shown in Fig. 1. In addition, the sealing stripsare so arranged, contrary to the showing of Fig. 1, that the sealingstrip 6 encloses the passage openings 3 and 5 whereas the sealing strips7 and 8 separately enclose the passage openings 4 and 2, respectively.

Spacing projections 9 on one flat surface of the plate 1 formed bycorresponding impressions in the opposite fiat surface of the plate aredisposed in such a manner that either the sealing strips are disposed inaccordance with Fig. 1 or in accordance with Fig. 2, all sealing stripswill extend between rows of such projections and in close proximitythereto. These projections, in addition, are disposed in such a mannerthat, when two identical plates are superimposed as they would be in astack of plates as illustrated in Fig. 3, with their corresponding flatsurfaces facing the same direction and with one plate rotated 180 in itsplane relative to the other plate, the spacing projections of one platewill engage the other plate in a staggered relation to the spacingprojections corresponding to the impressions of said other plate.

In this position of the plates the spacing projections prevent lateraldisplacement of the sealing strips between the plates which will bestill more apparent from a consideration also of Fig. 4. In a platestack compressed by clamping end plates, those spacing projections whichare disposed exteriorly of the sealing strip will act to preventany pairof adjacent plates from getting spread apart at any such place due tolateral pressure exerted by the sealing strip, and thus prevent thesealing strip from being released or flexing laterally outwards.

In the embodiment illustrated in Figs. 1 to 4, the spacing projectionsadjacent one side of the se ling strip areso disposed asto be oifset inthe longitudinal direction illustrated in Figs. 6 and 8, which, inaddition, show a plate 1d of an alternative structural arrangementwhich, in accordance with prior practice, has formed therein animpressed channel for an endless sealing strip do.

It has been found that the mereprovision of such a channel willnotafford adequate security against the sealing strip getting blown out athigh pressures. However', in combination with the spacing projectionsaccording to-the present invention full safety against this dangerwill'be ensured, as willbeclearly apparent from Fig. 8. Fig.9"illustrates a modification of the arrangement of Fig. 8, .themodification consisting in the feature that the spacing projections havebeen-impressed from the sameiiat surface of theplate as the channel 10.The lateral sealing-supporting.efiiciency is virtually the same as thatof the arrangement illustrated in Fig. 8.

:Fig 10 illustrates a fragmentary border portion of a plate lb in whichthe spacingprojections 9b and 9c are in the form of ridges or ribsengaging the sealing strip at their end surfaces. Theridges 9b situatedextcriorly of the sealing strip extend at right angles to the latter.The ridges 9c situated interiorly of the sealing strip extend at anoblique angle to the sealing strip in order to cause any two such plateshaving their respective ridges 9c crossing each other when superimposedas in a plate stack to support each other by the ridges or ribs of oneofthe plates while maintaining the flow passage unobstructed for theheat-exchanging fluid between the plates interiorly of the sealingstrip, as will lac-apparent from Fig. 12. The ridges 9b could bearranged obliquely as well, for instance as continuati-ons of theridges9c, and crossing each other in the operative position of any two platesin the pile so as to form supporting andspacing elements between suchplates, also exteriorlyof the sealing-strip. Figs. 10 and 11 incombination, however, illustrate an example in which the ridges 9b ofone plate are arranged centrally between, and in parallel relation to,identical ridges of the other plate.

In the embodiments illustrated in Figs. 1 to 9, for the sake of clarity,the spacing and strip-guiding projections-of each row are shown asspaced at larger intervals than would often be suitable in actualpractice in order safely to prevent a sealing strip deformable in alldirections from fiexing'out along its non-guided portions. Fig. 10however, also in this respect corresponds to a practical embodiment. Inmany cases, however,spaces of the order of magnitude indicated in theother figures could also be satisfactory in combination with a sealingstrip which is reinforced so a's'to be able, at least at in lateraldirection beyond the remainder of the member to enable the sealingelement, by said central portions, to engage the spacing projectionswithout any possibilty of sliding up the fillets 17 around the base ofthe projections inevitably involved in the pressing operatio-n, whichaction would cause twisting of the sealing strip-member. If such a rigidsealing member is to be rearrangeable from a position as according toFigure 1 into the position illustrated in Figure 2, this operation couldnot be executed practically in connection with a rte-establishment ofthe sealing member into its new shape but should be carried out simplyafter turning the sealing member 180 about an axis extending in theplane of the loop formed by said member. In order to cause the sealingmember to be accommodated properly also in this reversed position, it ismade symmetrical relative to the center plane of the sealing member. Itwould be throughout possible, of course, also to produce an integralone-piece soft sealing strip having such a symmetrical contour, and totreat the latter in the same'manner as the former upon rearrangement ofthe same.

It is to be understood that the embodiments described hereinbefore inconjunction with the accompanying drawings have been chosen merely byway of example, and that many other modifications are possible withoutdeparting'from the scope of the invention, both by further combining theembodiments exemplified, and by directly modifying these embodiments.

What we 'claim and desire to secure by Letters Patent is:

1. A heat exchanger comprising in combination a plurality of heattransmission plates integrally formed into their final shape out ofthinplate material and arranged in spaced stacked relationship, stringshaped circumferefitial bor der packings between each pair of adjacentheat transmission plates, said packings running along edge portions ofsaid plates at a distance from the free edges thereof and being directlyopposite each other when viewed in a direction perpendicular to theplates, said edge portions outside the packings having integrally formedspacers between adjacent edge portions of each pair of adjacent heattransmission plates, said spacers being arranged in a row in closelyspaced relation to each other along and close to the outer side of thepacking and consisting of protrusions on one side of the edge portion ofone of the adjacent plates formed by corresponding impressions in theother side of said edge portion, a1l such spacers protruding in the samedirectiori in the heat exchanger and abutting against the adreasonablespaces between the-guiding supports, to resist deformation by pressuresacting'along the planes of the plates. As an example of such aconstructional form of -a-re inforced sealing strip of a type which isknown per ,se-except, for a novel feature of importance in the actualconnection, reference is now made to Figure 13. This sealing member orpacking 11 comprises a strip 12 of metal or any suitable other materialof a considerably higher mechanical strength than that of the sealingsurfaces proper, and having a cross-sectional contour in the form of alying I embracing on its both sides sealing insertstrips 13 and14,'respectively, for instance of rubber or any suitable plasticmaterial, such as Teflon or the like.

The novel feature of this'construction resides in that themetal strip isformed along thecentral portions of the two lateral edges 15 and 16,respectively, of the sealing'member-in such a manner as to projectsufficiently jacent edge portion of an adjacent heat transmission platebetween spacer forming impressions therein.

2. A heat exchanger as claimed in claim 1 wherein the spacers outsidethe packing are arranged to form the only support for the packing .inits lateral outward direction.

References fiited in the file of this patent UNITED STATES PATENTS2,039,216 Feldmeier Apr. 28, 1936 2,203,123 Astle June 4, 1940 2,217,567Seligman et al. Oct. 8, 1940 2,281,754 Dalzell May 5, 1942 FOREIGNPATENTS 537,477 Great Britain June 24, 1941 OTHER REFERENCES Ser. No.402,669, News (A. P. (3.), published May 25, 1943.

